1. Field of the Invention
This invention relates to a non-catalytic method for the preparation of N-(3-dimethylaminopropyl)methacrylamide. More particularly, this invention relates to a method for the preparation of N-(3-dimethylaminopropyl)methacrylamide from N-(3-dimethylaminopropyl)-3-dimethylaminopropyl-2-methylpropionamide using a continuous tubular pyrolysis reactor.
2. Prior Art
Moss et al. U.S. Pat. No. 3,878,247 discloses a process for the production of N-(tertiary aminoalkyl) acrylamides in which an acrylic acid is first reacted with an excess of a tertiary aminoalkylamine to form a beta-aminopropionamide intermediate. In accordance with the Moss et al. invention, the propionamide intermediate is decomposed by pyrolysis at a temperature of 180.degree. to 300.degree. C. to the desired N-(tertiary aminoalkyl) acrylamide product and to a recyclable tertiary aminoalkylamine. By-product impurities are formed during the pyrolysis reaction and since the final product is a reactive vinyl monomer, Moss et al. teach that the product amine and the cleaved tertiary amino alkylamine should be taken overhead from the reaction mixture as formed.
U.S. Pat. No. 4,251,461 discloses an improvement in the pyrolysis reaction disclosed by Moss et al. wherein the beta-aminopropionamide is held in an atmospheric holding tank at 150.degree. to 220.degree. C. for 8 to 72 hours prior to pyrolysis in order to reduce the formation of by-product impurities.